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Role of lake regulation on glacier fed rivers in enhancing salmon productivity: The Cook Inlet watershed south central Alaska, USA

Hydrological Processes

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DOI: 10.1002/1099-1085(200011/12)14:16/17<3149::AID-HYP139>3.0.CO;2-Y

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Abstract

Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet. This paper examines the ways in which the regulation of glacier-fed rivers by proglacial lakes affects salmon productivity, with particular reference to the Kenai River. Salmon escapement per unit channel length on the Kenai River is between two and ten times that found for rain-and-snowmelt dominated rivers and glacier-fed rivers lacking lake regulation. Lakes are shown to influence biological processes in glacier-fed rivers by attenuating peak flows, sustaining high flows throughout the summer, supplementing winter low flows, settling suspended sediment, and increasing river temperatures. Downstream from large lakes, glacier-fed rivers are less disturbed, channels are relatively stable and have well-developed salmonid habitats. The positive influences are indicated by the high diversity and abundances of benthic macroinvertebrates, which are important food resources for juvenile salmonids. High summer flows allow access for up-river salmon runs and lakes also provide both overwintering and rearing habitat. Copyright ?? 2000 John Wiley & Sons, Ltd.Rivers fed by glaciers constitute a major part of the freshwater runoff into the Cook Inlet basin of south-central Alaska. This basin is very important to the economy of the State of Alaska because it is home to more than half of the population and it supports multi-million dollar commercial, subsistence and sport fisheries. Hence an understanding of how glacial runoff influences biological productivity is important for managing rivers that drain into Cook Inlet. This paper examines the ways in which the regulation of glacier-fed rivers by proglacial lakes affects salmon productivity, with particular reference to the Kenai River. Salmon escapement per unit channel length on the Kenai River is between two and ten times that found for rain-and-snowmelt dominated rivers and glacier-fed rivers lacking lake regulation. Lakes are shown to influence biological processes in glacier-fed rivers by attenuating peak flows, sustaining high flows throughout the summer, supplementing winter low flows, settling suspended sediment, and increasing river temperatures. Downstream from large lakes, glacier-fed rivers are less disturbed, channels are relatively stable and have well-developed salmonid habitats. The positive influences are indicated by the high diversity and abundances of benthic macroinvertebrates, which are important food resources for juvenile salmonids. High summer flows allow access for up-river salmon runs and lakes also provide both overwintering and rearing habitat.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Role of lake regulation on glacier fed rivers in enhancing salmon productivity: The Cook Inlet watershed south central Alaska, USA
Series title:
Hydrological Processes
DOI:
10.1002/1099-1085(200011/12)14:16/17<3149::AID-HYP139>3.0.CO;2-Y
Volume
14
Issue:
16-17
Year Published:
2000
Language:
English
Publisher:
John Wiley & Sons Ltd
Publisher location:
Chichester, United Kingdom
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
First page:
3149
Last page:
3159
Number of Pages:
11